Vises are used in machine work in many ways and are referred to generally as machine vises, holding accuracy being a requirement, especially for production work; whether it be a bench vise, or a machine tool vise. For example, a milling machine vises are universally used and characterized by the installation thereon of soft jaws adapted to the particular work piece configuration involved. It is this soft jaw installation with which this invention is concerned, it being a general object of this invention to provide inherently accurate soft jaw installation in machine vises as they are commonly manufactured and with but slight modification thereto in some instances.
Machine vises are of high quality, in that the jaw faces are and remain parallel. Vise construction varies, a typical machine vise involving a base with accurately ground ways upon which a fixed jaw and a moveable clamp jaw are accurately mounted, and the opposing faces of the jaws ground flat and parallel one with the other. It is an object of this invention to ensure duplication of said jaw parallelism in the soft jaws separately applied thereto. In practice, each vise jaw has widely spaced threaded openings to receive fasteners that secure the soft jaws in working position. Accordingly, the machine vise receives jaws that are replaceable.
Heretofore, difficulty has been experienced in accurately installing soft jaws or the like to the flat accurately machined faces of the vise jaws. That is, the soft jaws have not always seated flat and/or contiguous to the vise jaw faces, and most often develop looseness between and away from the widely spaced fasteners. A solution to this problem has been to add features such as intermediate screw fasteners, but this may not be possible with some vise constructions, and in any case is a redundant measure, costly and time consuming; also requiring checking procedures with dial indicators and the like. Accordingly, it is an object of this invention to advantageously utilize the existing widely spaced fastener openings, without resort to redundant screw fasteners or costly mechanical arrangements, and without any additional parts other than the basic soft jaw and a pair of fasteners, in each instance.
A desirable feature for a soft jaw is that it be devoid of any intrusion upon its working face. In other words, that its working face be unobstructed and of substantial thickness for adaptation to a work piece. In this respect, the soft jaw employed herein is characterized by its T-slot configuration, much the same as employed in my U.S. Pat. No. 4,898,371 issued Feb. 6, 1990. However, the complexities of my said patent are avoided herein and a special vise construction is not required.
It is an object of this invention to employ T-slot soft jaws with T-nut fasteners or the like, whereby the soft jaws are pulled coextensively to the machine faces of the vise jaws. In carrying out this invention, it is an object to prestress the soft jaw installation whereby the soft jaw is pulled coextensively tight into the vise jaw face. In the basic embodiment of this invention the soft jaw per se is prestressed by arcuately forming the same and is secured to the vise jaw face by straight and flat T-nuts or a T-bar. In a second embodiment of this invention the soft jaw is straight and flat while the T-bar is prestressed by arcuately forming the same. In a third embodiment of this invention the T-nuts are reversely prestressed by arcuately forming the same. And, in a fourth embodiment of this invention both the soft jaw and T-bar are prestressed by arcuately forming the same.
The precision jaws of a machine vise are characteristically of limited height, for example 1.5 inch, whereas the height requirements of soft jaws is often substantially greater. However, this increased height has been restricted in the past, due to the inherent weakness in the soft jaw metal, for example aluminum, commonly used in their construction. Accordingly, it is an object of this invention to reinforce the extended height of soft jaws with the fastener means employed to secure the same to the vise jaws. In carrying out this invention, the fastener means is preferably an elongated T-nut or T-bar configuration and made of durable steel that has considerably higher strength properties than soft aluminum and the like. In practice, the fastener means is what will be referred to as a T-bar and made of high tensile heat treated steel or the like. It is to be understood that the material quality of the reinforcement fastener means can vary as required.